This invention relates to methods and devices for treating soft tissue disorders, and more particularly to laser therapeutic methods and devices.
Therapeutic lasers are useful in the treatment of certain types of tissue disorders. See, e.g., U.S. Pat. No. 4,215,694 to Isakov et al., U.S. Pat. No. 4,640,283 to Sawa et al., U.S. Pat. No. 4,671,285 to Walker, U.S. Pat. No. 4,724,835 to Liss et al., U.S. Pat. No. 4,930,504 to Diamantopoulos et al., U.S. Pat. No. 4,930,505 to Hatje, U.S. Pat. No. 4,966,144 to Rochkind et al., U.S. Pat. No. 5,029,581 to Kaga et al., U.S. Pat. No. 5,051,823 to Cooper et al., U.S. Pat. No. 5,150,704 to Tatebayashi et al., U.S. Pat. No. 5,320,619 to Badawi, U.S. Pat. No. 5,344,434 to Talmore, U.S. Pat. No. 5,409,482 to Diamantopoulos, U.S. Pat. No. 5,445,146 to Bellinger, U.S. Pat. No. 5,445,608 to Chen, U.S. Pat. No. 5,464,436 to Smith, U.S. Pat. No. 5,514,168 to Friedman, U.S. Pat. No. 5,616,140 to Prescott, U.S. Pat. No. 5,649,924 to Everett et al., U.S. Pat. No. 5,755,752 to Segal.
Laser therapy (i.e., Low Level Laser Therapy or LLLT) generally requires the injured tissue to be exposed directly to the laser light for predetermined intervals of time. Exposure to laser light not only lessens the pain associated with certain disorders, but actually speeds the healing of the treated tissues. The wavelength of the laser light, the intensity of the laser light and the exposure time are important factors when selecting a specific treatment protocol for a specific disorder.
The wavelength of the laser light affects its ability to penetrate through overlaying tissues, such as skin, to reach the tissues and molecules of interest. For example, red light is attenuated by most tissues (1/e2 attenuation), and thus the penetration depth is less than 1 cm into such tissues, whereas near-infrared (NIR) light is less attenuated by most tissues, and thus can penetrate more than 1 cm into such tissues.
The wavelength of the laser light also affects it ability to promote biological pathways for healing injured tissues. For example, the quantum energy of near-infrared photons is small, and thus near-infrared photons have a relatively low potential to electronically exciting biomolecules. On the other hand, the quantum energy of red wavelength photons is sufficient to achieve electronic excitation of biomolecules, potentially promoting direct photochemical and photobiological effects in target tissues.
The precise nature of the molecular events caused by narrow bandwidth red and near-infrared light irradiation is still under investigation. However, clinical evidence suggests that biostimulation using red light and biostimulation using near-infrared light each promotes wound healing and/or relieves the symptoms of rheumatoid arthritis. See, e.g., Mester et al., xe2x80x9cWound-Healing,xe2x80x9d 1 Laser Therapy 7-15 (1989), and Asada et al., xe2x80x9cDiode Laser Therapy for Rheumatoid Arthritis: A Clinical Evaluation of 102 Joints Treated with Low Reactive-Level Laser Therapy (LLLT) 1 Laser Therapy 147-152 (1989).
The intensity of the laser light used to treat an injury is another factor in its effectiveness. Applying a therapeutically insufficient intensity of laser light to an injury has no desirable effects, but applying excess intensity can cause undesirable heating, burning and even vaporization of tissue.
The total exposure time is also an important factor in laser therapy, as combined with irradiance it determines the total deposited energy. If an injury is not exposed to laser light for an appropriate interval of time, insufficient healing may result. Excess exposure to laser light can injure the target tissues.
As the target tissue for laser therapy is typically subcutaneous, and the factors controlling the penetrability of a patient""s skin (e.g., thickness, fat content, color, etc.) vary from patient to patient, it has been difficult to employ one ideal protocol for all patients. That is, the target tissue is typically located at a certain depth xe2x80x9cZ0xe2x80x9d below the surface, and the energy delivered to depth xe2x80x9cZ0xe2x80x9d has been difficult to monitor and control. Protocols can be manually adjusted to the particular patient, but this adds complexity to the treatment, and more heavily relies on the proper training of medical personnel.
A variety of laser systems in the laser therapy and laser surgery arts have been proposed that intelligently control laser beam intensity and duration using target monitoring and feedback (real-time and otherwise). See, e.g., U.S. Pat. No. 5,657,760 to Ying, U.S. Pat. No. 5,423,801 to Marshall, U.S. Pat. No. 5,354,323 to Whitebook, U.S. Pat. No. 5,154,707 to Rink et al., U.S. Pat. No. 5,050,597 to Daikuzono, U.S. Pat. No. 4,973,848 to Kolobanov et al., and U.S. Pat. No. 4,644,948 to Lang et al.
All references cited herein are incorporated herein by reference in their entireties.
The invention provides a method for treating a patient having a disorder, said method comprising:
is irradiating a tissue of said patient with a near-infrared laser light having a first therapeutically effective intensity and with a visible laser light having a second therapeutically effective intensity;
automatically monitoring said irradiated tissue; and
automatically terminating said irradiating when said monitoring indicates that said near-infrared laser light and said visible laser light have been applied to said tissue for a duration therapeutically effective to treat said disorder.
Also provided is a laser apparatus adapted to perform this method of the invention, said laser apparatus comprising:
a near-infrared light laser;
a visible light laser;
a power supply in electrical communication with said lasers;
waveguides for guiding beams from said lasers to a common focal point on a surface of a target tissue;
detectors adapted to detect radiation remitted from said target surface along a radius originating at said common focal point; and
control logic electronics adapted to automatically adjust an output of said lasers based on said remitted radiation detected by said detectors.
The invention also provides a method for administering a predetermined dose of radiation to a distal target tissue, said method comprising:
irradiating a proximal tissue adjacent said distal target tissue with at least one laser light which penetrates through said proximal tissue to administer radiation to said distal target tissue;
automatically monitoring said proximal tissue to determine whether to terminate said irradiating, said monitoring comprising detecting a radial dependence of a diffuse reflectance from a surface of said proximal tissue of said at least one laser light; and
automatically terminating said irradiating when said monitoring indicates that said predetermined dose of laser light has been applied to said distal target tissue.
A laser apparatus adapted to perform this method of the invention is also provided. The laser apparatus comprises:
at least one laser;
a power supply in electrical communication with said at least one laser;
at least one detector adapted to detect radiation remitted from two points on said target surface along a radius originating at a focal point of said at least one laser on said proximal tissue; and
control logic electronics adapted to automatically adjust an output of said at least one laser based on said remitted radiation detected by said at least one detector.